Travel Restrictions for Lithium and Lithium Ion Batteries http://safetravel.dot.gov/documents/airline_passengers_and_batteries. pdf ... In carry-on baggage, there is no limit to the number of consumer-size batteries or battery- powered devices that a passenger can carry for "personal use". ... http://safetravel.dot.gov/documents/airline_passengers_and_batteries. pdf
1. Recharge the battery on the day before or on the day it is to be used. Even during non-use or storage, a charged battery will gradually discharge and lose its power .